The invention relates to a method and an apparatus for position control of plant parts located within an objective field, in a shielded, highly radioactive cell of an atomic plant, in particular a large cell of a reprocessing plant for irradiated atomic fuels, hereinafter called hot cell.
These types of position controls serve for measuring changes of position of individual plant parts, in particular changes of position occasioned by aging, relative to a fixed reference system. Envisioned here are time spans of about 25 years or more. These types of systems need not necessarily operate fully automatically. Rather, it is possible here to also make use of interactively executed (between operator and device) procedures and/or apparatus. Essential here, however, is that the procedures (methods) and apparatus be laid out such that a person need not enter the hot cell.
Hot cells in which the reprocessing procedure is running off have, for example, dimensions of 100.times.25.times.20 m. If, for example, one sets a measurement accuracy for location determination of the component resulting in the total objective field at 1 mm, this then means that one needs, theoretically, to manage up to 4 billion measurement points. In view of a figure of this type, it can be recognized that high requirements are to be placed on suitable methods and apparatus for position control of the art mentioned. For example, the following conditions must suffice for methods and apparatus for position control suitable for hot cells:
high degree of measurement accuracy and/or resolution capability (e.g. .+-.1 mm)
large field of measurement and viewing, respectively (100.times.20 m)
as little as possible storage (memory) requirement
long-term reproduceability of the conditions of measurement (capability for comparing data that are far apart in time)
capability of remote operation
as little as possible additional expense for hardware in the hot cells
as simple as possible operation.